Punch



Aug. 26. 1924. 1,506,480

H. GRADE PUNCH Filed Feb. 6, 1923 [)1 Van far HANS GRADE.

1/1 messes ietented Aug. 26, 1924.

UNITED STATES HANS GRADE. OF BOB-K, GERMANY.

PUNCH.

Application filed February 6, 1923.

To all whom it may concern:

Be it known that I, HANs GRADE, citizen of the Republic of Gern'iany,residing at Bork, i. /M., Germany, have invented certain new and usefulImprovements in Punches, of which the following is a specification.

The invention relates to the construction oi the cutting edges of punchheads for the stamping of sheet metal. The new embodiment of the cuttingsurfaces serves to increase the eificiency of the punch, i. e., toiicrcase the total cutting surface and lessen the amount of powerrequired. In general, a plane cutting surface is employed whichsimultaneously penetrates through the material ,upon the whole cuttingline. Hand punches are known with one pie-cutting section. Punch headsare also known with several pro-cutting sections and one-sidedlyarranged cutting surfaces, whereby the precutting section runs into asharp point. In the case of the new embodiment of the cutting surfacesthe cut commences at two or more definite points, and upon furtheroperation the penetration extends symmetrically along the whole cuttingline. This cutting line may be either straight or curved.

In the drawing the embodiment of the punch head is diagrammaticallyshown, in which- Figs. l3 illustrate details of a round punch;

Figs. 4L6 details of a square punch.

With the round punch the cutting edge lies upon a cylindrical surface,so that the cutting line Fig. 2 appears in the development.

hen punching, the points 1 contact first with the blank, and finally thepoints 2. In the case of the square punch according to Fig. 4 all fourcutting edges are rounded off so that the points 3 contact with theblank first, and finally the points 4. The cutting line proceeds from 1and 3 respectively in symmetrical manner in order to preventdisplacement of the material. An obtuse angle, as shown in dotted linesin Fig. 4;, may be employed for the cutting edges in- Serial No.617,324.

stead of the curved embodiment. The difference between the highest andlowest points of the cutting line must be greater in accordance with thestrength of the material to be out. If, for example, a punch as maximumaccomplishment stamps through 3 mm. sheet metal, by increasing thedifference between the highest and lowest points of the cutting line by3 mm., 6 mm. metal may be stamped. The loud noise otherwise customarywith punching, produced by the tension of the material, is eliminated.In the case of larger punches with complicated cutting it is absolutelynecessary to commence with the cutting at several points, and ifpossible in the manner that the entering points are divided uniformlyon. the circumference. In this way the bending of the punch isprevented, and at the same time the material is held firmly at severalpoints and cannot be displaced.

The dotted lines in Fig. 4 illustrate a square punch in which the edgesof its working face are not arcs, but are composed of straight lineswhich form angles.

-What I claim is 1. In combination, a punch, Working within an aperture,said punch having a cutting edge coextensive with its periphery, theworking face of the punch including this cutting edge, said edge havinga portion adapted to first engage the work and deform it into the punchaperture.

2. In combination, a punch, a die having an aperture therein, said punchhaving a cutting edge, said edge entering said aperture at two pointssimultaneously, said entering action proceeding symmetrically away fromeach entering point.

.3. A punch having a working face, a cutting edge on said punchcoextensive with the face periphery, said face being a part of acylindrical surface.

In testimony whereof I have afliXed my signature in the presence of awitness.

HANS GRADE.

Witness:

E. H6LTZERMANN.

